/*
 * Copyright 2002-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.core.codec;

import java.util.Map;

import io.netty.buffer.ByteBuf;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;

import org.springframework.core.ResolvableType;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.lang.Nullable;
import org.springframework.util.MimeType;
import org.springframework.util.MimeTypeUtils;

/**
 * Encoder for {@link ByteBuf ByteBufs}.
 *
 * @author Vladislav Kisel
 * @since 5.3
 */
public class NettyByteBufEncoder extends AbstractEncoder<ByteBuf> {

    public NettyByteBufEncoder() {
        super(MimeTypeUtils.ALL);
    }


    @Override
    public boolean canEncode(ResolvableType type, @Nullable MimeType mimeType) {
        Class<?> clazz = type.toClass();
        return super.canEncode(type, mimeType) && ByteBuf.class.isAssignableFrom(clazz);
    }

    @Override
    public Flux<DataBuffer> encode(Publisher<? extends ByteBuf> inputStream,
                                   DataBufferFactory bufferFactory, ResolvableType elementType, @Nullable MimeType mimeType,
                                   @Nullable Map<String, Object> hints) {

        return Flux.from(inputStream).map(byteBuffer ->
                encodeValue(byteBuffer, bufferFactory, elementType, mimeType, hints));
    }

    @Override
    public DataBuffer encodeValue(ByteBuf byteBuf, DataBufferFactory bufferFactory,
                                  ResolvableType valueType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {

        if (logger.isDebugEnabled() && !Hints.isLoggingSuppressed(hints)) {
            String logPrefix = Hints.getLogPrefix(hints);
            logger.debug(logPrefix + "Writing " + byteBuf.readableBytes() + " bytes");
        }
        if (bufferFactory instanceof NettyDataBufferFactory) {
            return ((NettyDataBufferFactory) bufferFactory).wrap(byteBuf);
        }
        byte[] bytes = new byte[byteBuf.readableBytes()];
        byteBuf.readBytes(bytes);
        byteBuf.release();
        return bufferFactory.wrap(bytes);
    }
}
